Multiple scattering and attenuation corrections in Deep Inelastic Neutron Scattering experiments

Multiple scattering and attenuation corrections in Deep Inelastic Neutron Scattering experiments are analyzed. The theoretical basis is stated, and a Monte Carlo procedure to perform the calculation is presented. The results are compared with experimental data. The importance of the accuracy in the description of the experimental parameters is tested, and the implications of the present results on the data analysis procedures is examined.Comment: 19 pages, 8 figure

Inflation Physics from the Cosmic Microwave Background and Large Scale Structure

Fluctuations in the intensity and polarization of the cosmic microwave background (CMB) and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time. The next generation of CMB and large-scale structure (LSS) experiments are poised to test the leading paradigm for these earliest moments---the theory of cosmic inflation---and to detect the imprints of the inflationary epoch, thereby dramatically increasing our understanding of fundamental physics and the early universe. A future CMB experiment with sufficient angular resolution and frequency coverage that surveys at least 1 of the sky to a depth of 1 uK-arcmin can deliver a constraint on the tensor-to-scalar ratio that will either result in a 5-sigma measurement of the energy scale of inflation or rule out all large-field inflation models, even in the presence of foregrounds and the gravitational lensing B-mode signal. LSS experiments, particularly spectroscopic surveys such as the Dark Energy Spectroscopic Instrument, will complement the CMB effort by improving current constraints on running of the spectral index by up to a factor of four, improving constraints on curvature by a factor of ten, and providing non-Gaussianity constraints that are competitive with the current CMB bounds

Body mass index and subsequent fracture risk: a meta-analysis to update FRAX®

The aim of this international meta-analysis was to quantify the predictive value of body mass index (BMI) for incident fracture and relationship of this risk with age, sex, follow-up time and bone mineral density (BMD). 1 667 922 men and women from 32 countries (63 cohorts), followed for a total of 16.0 million person-years were studied. 293 325 had femoral neck BMD measured (2.2 million person-years follow-up). An extended Poisson model in each cohort was used to investigate relationships between WHO-defined BMI categories (Underweight:<18.5 kg/m2; Normal:18.5-24.9 kg/m2; Overweight:25.0-29.9 kg/m2; Obese I:30.0-34.9 kg/m2; Obese II:≥35.0 kg/m2) and risk of incident osteoporotic, major osteoporotic and hip fracture (HF). Inverse-variance weighted β-coefficients were used to merge the cohort-specific results. For the subset with BMD available, in models adjusted for age and follow-up time, the hazard ratio (95%CI) for HF comparing underweight with normal weight was 2.35 (2.10-2.60) in women and for men was 2.45 (1.90-3.17). HF risk was lower in overweight and obese categories compared to normal weight [obese II vs normal: women 0.66 (0.55-0.80); men 0.91 (0.66-1.26). Further adjustment for femoral neck BMD T-score attenuated the increased risk associated with underweight [underweight vs normal: women 1.69 (1.47-1.96); men 1.46 (1.00-2.13)]. In these models, the protective effects of overweight and obesity were attenuated, and in both sexes the direction of association reversed to higher fracture risk in Obese II category [Obese II vs Normal: women 1.24 (0.97-1.58); men 1.70 (1.06-2.75)]. Results were similar for other fracture outcomes. Underweight is a risk factor for fracture in both men and women regardless of adjustment for BMD. However, whilst overweight/obesity appeared protective base models, they became risk factors after additional adjustment for femoral neck BMD, particularly in the Obese II category. This effect in the highest BMI categories was of greater magnitude in men than women. These results will inform the second iteration of FRAX

Family history of fracture and fracture risk: a meta-analysis to update the FRAX® risk assessment tool

Summary In the largest meta-analysis of international cohorts to date, a family history of fracture is confirmed as a significant BMD-independent predictor of future fracture risk. Parental and sibling histories of fracture carry the same significance for future fracture, including the impact of family hip fracture on future hip fracture risk. Purpose We have undertaken a meta-analysis of international prospective cohorts to quantify the relationship between a family history of fracture and future fracture incidence. Methods The analysis dataset comprised 350,542 men and women from 42 cohorts in 29 countries followed for 2.8 million person-years. We investigated the relationship between family history of hip fracture or any fracture and the risk of any clinical fracture, any osteoporotic fracture, major osteoporotic fracture (MOF), and hip fracture alone using an extended Poisson model in each cohort. Models were adjusted for current age, sex, BMD, and follow-up time. Results As no difference in influence of family history of fracture was seen between genders, results are presented for men and women combined. A parental history of hip fracture was associated with a higher risk of incident fracture across all fracture outcome categories, with a stronger relationship with future hip fracture (hazard ratios (HR, 95% CI) for hip and MOF 1.37, 1.23–1.52 and 1.19, 1.12–1.27, respectively). Associations were slightly reduced but remained significant when additionally adjusted for BMD and did not vary by baseline offspring age, follow-up time, or parent affected. In a more limited analysis, parental history of any fracture or a sibling history of hip or any fracture showed similar associations to those observed with parental history of hip fracture. Conclusions A family history of fracture is confirmed as a significant BMD-independent predictor of future fracture risk. While parental hip fracture appears the strongest factor for future hip fracture, a family history of other fractures might be appropriate for inclusion in future iterations of the FRAX tool

Both \u3ci\u3eLymantria dispar\u3c/i\u3e Nucleopolyhedrovirus \u3ci\u3eEnhancin\u3c/i\u3e Genes Contribute to Viral Potency

Enhancins are a group of proteins first identified in granuloviruses (GV) that have the ability to enhance nuclear polyhedrosis virus potency. We had previously identified an enhancin gene (E1) in the Lymantria dispar multinucleocapsid nucleopolyhedrovirus (LdMNPV) (D. S. Bischoff and J. M. Slavicek, J. Virol. 71:8133–8140, 1997). Inactivation of the E1 gene product within the viral genome lowered viral potency by an average of 2.9-fold. A second enhancin gene (E2) was identified when the entire genome of LdMNPV was sequenced (Kuzio et al., Virology 253:17–34, 1999). The E2 protein exhibits approximately 30% amino acid identity to the LdMNPV E1 protein as well as the enhancins from Trichoplusia ni GV, Pseudaletia unipuncta GV, Helicoverpa armigera GV, and Xestia c-nigrum GV. Northern analysis of viral RNA indicated that the E2 gene transcripts are expressed at late times postinfection from a consensus baculovirus late promoter. The effect of the enhancin proteins on viral potency was investigated through bioassay using two recombinant viruses, one with a deletion in the E2 gene (E2del) and a second with deletion mutations in both enhancin genes (E1delE2del). The enhancin gene viral constructs were verified by Southern analysis and shown not to produce enhancin gene transcripts by Northern analysis. The E2del virus exhibited an average decrease in viral potency of 1.8-fold compared to wild-type virus. In the same bioassays, the recombinant virus E1cat, which does not produce an E1 gene transcript, exhibited an average decrease in viral potency of 2.3-fold compared to control virus. The E1delE2del virus exhibited an average decrease in viral potency of 12-fold compared to wild-type virus. Collectively, these results suggest that both LdMNPV enhancin genes contribute to viral potency, that each enhancin protein can partially compensate for the lack of the other protein, and that both enhancin genes are necessary for wild-type viral potency

Activity-based enrichment of matrix metalloproteinases using reversible inhibitors as affinity ligands

Matrix metalloproteinases (MMPs) are zinc dependent metalloproteases characterized by the ability to cleave extracellular matrix and many other extracellular proteins. MMP activity is tightly regulated but disturbances in this regulation can contribute to various disease processes characterized by a progressive destruction of the extracellular matrix. The ability to profile classes of enzymes based on functionally related activities would greatly facilitate research about the involvement of MMPs in physiological and/or pathological states. Here we describe the characterization of an affinity sorbent using an immobilized reversible inhibitor as a stationary phase for the activity-based enrichment of MMPs from biological samples. With a ligand density of 9.8 mM and binding constant of 58 mumol/l towards MMP-12, the capturing power of the affinity sorbent was strong enough to extract MMP-12 spiked into serum with high selectivity from relatively large sample volumes. Experiments with endogenous inhibitors revealed that MMP-12 extraction is strictly activity-dependent, offering powerful means to monitor NIMP activities in relation to physiological and/or pathological events by using affinity extraction as a first step in an MMP profiling method. (C) 2003 Elsevier B.V. All rights reserved